<!DOCTYPE HTML>
<html lang="zh-CN">


<head>
    <meta charset="utf-8">
    <meta name="keywords" content="jiodg45的博客">
    <meta name="description" content="">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <meta name="renderer" content="webkit|ie-stand|ie-comp">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="format-detection" content="telephone=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
    <!-- Global site tag (gtag.js) - Google Analytics -->


    <title>jiodg45的博客</title>
    <link rel="icon" type="image/png" href="/jiodg45/favicon.png">

    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/awesome/css/all.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/materialize/materialize.min.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/aos/aos.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/animate/animate.min.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/lightGallery/css/lightgallery.min.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/css/matery.css">
    <link rel="stylesheet" type="text/css" href="/jiodg45/css/my.css">

    <script src="/jiodg45/libs/jquery/jquery.min.js"></script>

<meta name="generator" content="Hexo 5.4.0">
<style>.github-emoji { position: relative; display: inline-block; width: 1.2em; min-height: 1.2em; overflow: hidden; vertical-align: top; color: transparent; }  .github-emoji > span { position: relative; z-index: 10; }  .github-emoji img, .github-emoji .fancybox { margin: 0 !important; padding: 0 !important; border: none !important; outline: none !important; text-decoration: none !important; user-select: none !important; cursor: auto !important; }  .github-emoji img { height: 1.2em !important; width: 1.2em !important; position: absolute !important; left: 50% !important; top: 50% !important; transform: translate(-50%, -50%) !important; user-select: none !important; cursor: auto !important; } .github-emoji-fallback { color: inherit; } .github-emoji-fallback img { opacity: 0 !important; }</style>
</head>




<body>
    <header class="navbar-fixed">
    <nav id="headNav" class="bg-color nav-transparent">
        <div id="navContainer" class="nav-wrapper container">
            <div class="brand-logo">
                <a href="/jiodg45/" class="waves-effect waves-light">
                    
                    <img src="/jiodg45/medias/logo.png" class="logo-img" alt="LOGO">
                    
                    <span class="logo-span">jiodg45的博客</span>
                </a>
            </div>
            

<a href="#" data-target="mobile-nav" class="sidenav-trigger button-collapse"><i class="fas fa-bars"></i></a>
<ul class="right nav-menu">
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/" class="waves-effect waves-light">
      
      <i class="fas fa-home" style="zoom: 0.6;"></i>
      
      <span>首页</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/tags" class="waves-effect waves-light">
      
      <i class="fas fa-tags" style="zoom: 0.6;"></i>
      
      <span>标签</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/categories" class="waves-effect waves-light">
      
      <i class="fas fa-bookmark" style="zoom: 0.6;"></i>
      
      <span>分类</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/archives" class="waves-effect waves-light">
      
      <i class="fas fa-archive" style="zoom: 0.6;"></i>
      
      <span>归档</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/about" class="waves-effect waves-light">
      
      <i class="fas fa-user-circle" style="zoom: 0.6;"></i>
      
      <span>关于</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/contact" class="waves-effect waves-light">
      
      <i class="fas fa-comments" style="zoom: 0.6;"></i>
      
      <span>留言板</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/jiodg45/friends" class="waves-effect waves-light">
      
      <i class="fas fa-address-book" style="zoom: 0.6;"></i>
      
      <span>友情链接</span>
    </a>
    
  </li>
  
  <li>
    <a href="#searchModal" class="modal-trigger waves-effect waves-light">
      <i id="searchIcon" class="fas fa-search" title="搜索" style="zoom: 0.85;"></i>
    </a>
  </li>
</ul>


<div id="mobile-nav" class="side-nav sidenav">

    <div class="mobile-head bg-color">
        
        <img src="/jiodg45/medias/logo.png" class="logo-img circle responsive-img">
        
        <div class="logo-name">jiodg45的博客</div>
        <div class="logo-desc">
            
            Never really desperate, only the lost of the soul.
            
        </div>
    </div>

    

    <ul class="menu-list mobile-menu-list">
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-home"></i>
			
			首页
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/tags" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-tags"></i>
			
			标签
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/categories" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-bookmark"></i>
			
			分类
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/archives" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-archive"></i>
			
			归档
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/about" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-user-circle"></i>
			
			关于
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/contact" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-comments"></i>
			
			留言板
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/jiodg45/friends" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-address-book"></i>
			
			友情链接
		</a>
          
        </li>
        
        
        <li><div class="divider"></div></li>
        <li>
            <a href="https://github.com/blinkfox/hexo-theme-matery" class="waves-effect waves-light" target="_blank">
                <i class="fab fa-github-square fa-fw"></i>Fork Me
            </a>
        </li>
        
    </ul>
</div>


        </div>

        
            <style>
    .nav-transparent .github-corner {
        display: none !important;
    }

    .github-corner {
        position: absolute;
        z-index: 10;
        top: 0;
        right: 0;
        border: 0;
        transform: scale(1.1);
    }

    .github-corner svg {
        color: #0f9d58;
        fill: #fff;
        height: 64px;
        width: 64px;
    }

    .github-corner:hover .octo-arm {
        animation: a 0.56s ease-in-out;
    }

    .github-corner .octo-arm {
        animation: none;
    }

    @keyframes a {
        0%,
        to {
            transform: rotate(0);
        }
        20%,
        60% {
            transform: rotate(-25deg);
        }
        40%,
        80% {
            transform: rotate(10deg);
        }
    }
</style>

<a href="https://github.com/blinkfox/hexo-theme-matery" class="github-corner tooltipped hide-on-med-and-down" target="_blank"
   data-tooltip="Fork Me" data-position="left" data-delay="50">
    <svg viewBox="0 0 250 250" aria-hidden="true">
        <path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path>
        <path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2"
              fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"></path>
        <path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z"
              fill="currentColor" class="octo-body"></path>
    </svg>
</a>
        
    </nav>

</header>

    



<div class="bg-cover pd-header post-cover" style="background-image: url('/jiodg45/medias/featureimages/0.jpg')">
    <div class="container" style="right: 0px;left: 0px;">
        <div class="row">
            <div class="col s12 m12 l12">
                <div class="brand">
                    <h1 class="description center-align post-title"></h1>
                </div>
            </div>
        </div>
    </div>
</div>




<main class="post-container content">

    
    <link rel="stylesheet" href="/jiodg45/libs/tocbot/tocbot.css">
<style>
    #articleContent h1::before,
    #articleContent h2::before,
    #articleContent h3::before,
    #articleContent h4::before,
    #articleContent h5::before,
    #articleContent h6::before {
        display: block;
        content: " ";
        height: 100px;
        margin-top: -100px;
        visibility: hidden;
    }

    #articleContent :focus {
        outline: none;
    }

    .toc-fixed {
        position: fixed;
        top: 64px;
    }

    .toc-widget {
        width: 345px;
        padding-left: 20px;
    }

    .toc-widget .toc-title {
        padding: 35px 0 15px 17px;
        font-size: 1.5rem;
        font-weight: bold;
        line-height: 1.5rem;
    }

    .toc-widget ol {
        padding: 0;
        list-style: none;
    }

    #toc-content {
        padding-bottom: 30px;
        overflow: auto;
    }

    #toc-content ol {
        padding-left: 10px;
    }

    #toc-content ol li {
        padding-left: 10px;
    }

    #toc-content .toc-link:hover {
        color: #42b983;
        font-weight: 700;
        text-decoration: underline;
    }

    #toc-content .toc-link::before {
        background-color: transparent;
        max-height: 25px;

        position: absolute;
        right: 23.5vw;
        display: block;
    }

    #toc-content .is-active-link {
        color: #42b983;
    }

    #floating-toc-btn {
        position: fixed;
        right: 15px;
        bottom: 76px;
        padding-top: 15px;
        margin-bottom: 0;
        z-index: 998;
    }

    #floating-toc-btn .btn-floating {
        width: 48px;
        height: 48px;
    }

    #floating-toc-btn .btn-floating i {
        line-height: 48px;
        font-size: 1.4rem;
    }
</style>
<div class="row">
    <div id="main-content" class="col s12 m12 l9">
        <!-- 文章内容详情 -->
<div id="artDetail">
    <div class="card">
        <div class="card-content article-info">
            <div class="row tag-cate">
                <div class="col s7">
                    
                          <div class="article-tag">
                            <span class="chip bg-color">无标签</span>
                          </div>
                    
                </div>
                <div class="col s5 right-align">
                    
                </div>
            </div>

            <div class="post-info">
                
                <div class="post-date info-break-policy">
                    <i class="far fa-calendar-minus fa-fw"></i>发布日期:&nbsp;&nbsp;
                    2021-04-10
                </div>
                

                

                

                

                
            </div>
        </div>
        <hr class="clearfix">

        

        

        <div class="card-content article-card-content">
            <div id="articleContent">
                <h1 id="Flutter概览"><a href="#Flutter概览" class="headerlink" title="Flutter概览"></a>Flutter概览</h1><p><a target="_blank" rel="noopener" href="https://segmentfault.com/a/1190000023622237?utm_source=tag-newest">https://segmentfault.com/a/1190000023622237?utm_source=tag-newest</a></p>
<h2 id="Flutter-Shape"><a href="#Flutter-Shape" class="headerlink" title="Flutter Shape"></a>Flutter Shape</h2><p>继承于<code>Object</code>类,描述Widget的轮廓信息,在paint阶段直接通过<code>Canvas</code>直接进行绘制</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">void</span> paint(Canvas canvas, Rect rect, { TextDirection? textDirection });</span><br></pre></td></tr></tbody></table></figure>

<p>下面是framework中<code>RoundedRectangleBorder</code>源码实现</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">///<span class="markdown"><span class="bullet">1.</span> 在paint阶段直接此方法</span></span></span><br><span class="line"><span class="keyword">void</span> paint(Canvas canvas, Rect rect, { TextDirection? textDirection }) {</span><br><span class="line">  <span class="keyword">switch</span> (side.style) {</span><br><span class="line">    <span class="keyword">case</span> BorderStyle.none:</span><br><span class="line">      <span class="keyword">break</span>;</span><br><span class="line">    <span class="keyword">case</span> BorderStyle.solid:</span><br><span class="line">      <span class="keyword">final</span> <span class="built_in">double</span> width = side.width;</span><br><span class="line">      <span class="keyword">if</span> (width == <span class="number">0.0</span>) {</span><br><span class="line">        canvas.drawRRect(borderRadius.resolve(textDirection).toRRect(rect), side.toPaint());</span><br><span class="line">      } <span class="keyword">else</span> {</span><br><span class="line">        <span class="keyword">final</span> RRect outer = borderRadius.resolve(textDirection).toRRect(rect);</span><br><span class="line">        <span class="keyword">final</span> RRect inner = outer.deflate(width);</span><br><span class="line">        <span class="keyword">final</span> Paint paint = Paint()</span><br><span class="line">          ..color = side.color;</span><br><span class="line">          <span class="comment">///<span class="markdown"><span class="bullet">2.</span> 根据画笔绘制inner和outer巨型区域</span></span></span><br><span class="line">        canvas.drawDRRect(outer, inner, paint);</span><br><span class="line">      }</span><br><span class="line">  }</span><br><span class="line">}</span><br><span class="line"> <span class="comment">///<span class="markdown">3.通过native层的`Canvas进行绘制</span></span></span><br><span class="line"> <span class="keyword">void</span> drawDRRect(RRect outer, RRect inner, Paint paint) {</span><br><span class="line">  <span class="keyword">assert</span>(_rrectIsValid(outer));</span><br><span class="line">  <span class="keyword">assert</span>(_rrectIsValid(inner));</span><br><span class="line">  <span class="keyword">assert</span>(paint != <span class="keyword">null</span>); <span class="comment">// ignore: unnecessary_null_comparison</span></span><br><span class="line">  _drawDRRect(outer._value32, inner._value32, paint._objects, paint._data);</span><br><span class="line">}</span><br><span class="line"><span class="keyword">void</span> _drawDRRect(Float32List outer,</span><br><span class="line">                 Float32List inner,</span><br><span class="line">                 <span class="built_in">List</span>&lt;<span class="built_in">dynamic</span>&gt;? paintObjects,</span><br><span class="line">                 ByteData paintData) native <span class="string">'Canvas_drawDRRect'</span>;</span><br></pre></td></tr></tbody></table></figure>

<p>其相关子类如下:</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br></pre></td><td class="code"><pre><span class="line">ShapeBorder (borders.dart)</span><br><span class="line">    BoxBorder (box_border.dart)</span><br><span class="line">        BorderDirectional (box_border.dart)</span><br><span class="line">        Border (box_border.dart)</span><br><span class="line">    InputBorder (input_border.dart)</span><br><span class="line">        _NoInputBorder (input_border.dart)</span><br><span class="line">        OutlineInputBorder (input_border.dart)</span><br><span class="line">        UnderlineInputBorder (input_border.dart)</span><br><span class="line">    _OutlineBorder (outline_button.dart)</span><br><span class="line">    OutlinedBorder (borders.dart)</span><br><span class="line">        BeveledRectangleBorder (beveled_rectangle_border.dart)</span><br><span class="line">        CircleBorder (circle_border.dart)</span><br><span class="line">        ContinuousRectangleBorder (continuous_rectangle_border.dart)</span><br><span class="line">        _RoundedRectangleToCircleBorder (rounded_rectangle_border.dart)</span><br><span class="line">        RoundedRectangleBorder (rounded_rectangle_border.dart)</span><br><span class="line">        _StadiumToCircleBorder (stadium_border.dart)</span><br><span class="line">        _StadiumToRoundedRectangleBorder (stadium_border.dart)</span><br><span class="line">        StadiumBorder (stadium_border.dart)</span><br><span class="line">    _CompoundBorder (borders.dart)</span><br></pre></td></tr></tbody></table></figure>

<h2 id="InputBorder"><a href="#InputBorder" class="headerlink" title="InputBorder"></a>InputBorder</h2><p>主要用于输入框的装饰，</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">/// <span class="markdown"><span class="bullet"> *</span> [UnderlineInputBorder], the default [InputDecorator] border which</span></span></span><br><span class="line"><span class="comment">/// <span class="markdown">   draws a horizontal line at the bottom of the input decorator's container.</span></span></span><br><span class="line"><span class="comment">/// <span class="markdown"><span class="bullet"> *</span> [OutlineInputBorder], an [InputDecorator] border which draws a</span></span></span><br><span class="line"><span class="comment">/// <span class="markdown">   rounded rectangle around the input decorator's container.</span></span></span><br><span class="line"><span class="comment">/// <span class="markdown"><span class="bullet"> *</span> [InputDecoration], which is used to configure an [InputDecorator].</span></span></span><br></pre></td></tr></tbody></table></figure>


<figure class="highlight c++"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">define</span> DART_BIND_ALL(CLASS, FOR_EACH)                              \</span></span><br><span class="line">  FOR_EACH(DART_NATIVE_CALLBACK)                                    \</span><br><span class="line">  <span class="function"><span class="keyword">void</span> <span class="title">CLASS::RegisterNatives</span><span class="params">(tonic::DartLibraryNatives* natives)</span> </span>{ \</span><br><span class="line">    natives-&gt;Register({FOR_EACH(DART_REGISTER_NATIVE)});            \</span><br><span class="line">  }</span><br><span class="line"></span><br></pre></td></tr></tbody></table></figure>

<h2 id="external关键字"><a href="#external关键字" class="headerlink" title="external关键字"></a>external关键字</h2><p>将定义和实现分离,在flutter framework中采用<code>external</code>关键字定义的方法,在<code>dart sdk</code>中实现, dart sdk将方法的实现定义在不同的平台上,以最常见的<code>Object</code>为例</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">@patch</span></span><br><span class="line"><span class="meta">@pragma</span>(<span class="string">"vm:entry-point"</span>)</span><br><span class="line"><span class="class"><span class="keyword">class</span> <span class="title">Object</span> </span>{</span><br><span class="line">  </span><br><span class="line">  <span class="meta">@patch</span></span><br><span class="line">  <span class="meta">@pragma</span>(<span class="string">"vm:exact-result-type"</span>, <span class="built_in">bool</span>)</span><br><span class="line">  <span class="meta">@pragma</span>(<span class="string">"vm:prefer-inline"</span>)</span><br><span class="line">  <span class="built_in">bool</span> <span class="keyword">operator</span> ==(<span class="built_in">Object</span> other) native <span class="string">"Object_equals"</span>; </span><br><span class="line"></span><br><span class="line">  <span class="meta">@patch</span></span><br><span class="line">  <span class="built_in">String</span> toString() native <span class="string">"Object_toString"</span>;</span><br><span class="line">  <span class="comment">// A statically dispatched version of Object.toString.</span></span><br><span class="line">  <span class="keyword">static</span> <span class="built_in">String</span> _toString(obj) native <span class="string">"Object_toString"</span>;</span><br><span class="line"></span><br><span class="line">  <span class="meta">@patch</span></span><br><span class="line">  <span class="meta">@pragma</span>(<span class="string">"vm:entry-point"</span>, <span class="string">"call"</span>)</span><br><span class="line">  <span class="built_in">dynamic</span> noSuchMethod(Invocation invocation) {</span><br><span class="line">    <span class="comment">// TODO(regis): Remove temp constructor identifier 'withInvocation'.</span></span><br><span class="line">    <span class="keyword">throw</span> <span class="keyword">new</span> NoSuchMethodError.withInvocation(<span class="keyword">this</span>, invocation);</span><br><span class="line">  }</span><br><span class="line"></span><br><span class="line">  <span class="meta">@patch</span></span><br><span class="line">  <span class="meta">@pragma</span>(<span class="string">"vm:exact-result-type"</span>, <span class="string">"dart:core#_Type"</span>)</span><br><span class="line">  <span class="built_in">Type</span> <span class="keyword">get</span> runtimeType native <span class="string">"Object_runtimeType"</span>; </span><br><span class="line">}</span><br></pre></td></tr></tbody></table></figure>

<h2 id="Widget树"><a href="#Widget树" class="headerlink" title="Widget树"></a>Widget树</h2><p>Widget用于描述一个组件的配置信息,类似一个model. 从继承链来看,它主要包括了3大类</p>
<ul>
<li><p>ProxyWidget: 代理Widget,它是一个抽象类,包含一个child,用于包装child,常用的子类有<code>ParentDataWidget</code>和<code>InheritedWidget</code>用于提供数据给child.</p>
</li>
<li><p>StatelessWidget: 复合性的Widget,可以在build构造函数中组合其它的widget,它是无状态的,每次build时它所对应的Element都会从树中移除</p>
</li>
<li><p>StatefulWidget: 也是复合性的Widget,与Stateless的区别就在于它有<code>GlobalKey</code>的加持,可以保存当前的state,维持数据生命周期,在build时候不会被释放</p>
</li>
<li><p>RenderObjectWidget: 它是实际用于渲染的widget,用于包装RenderObject,提供实际的渲染对象</p>
</li>
</ul>
<p>下面是Widget的继承链,列举了一些常用的widget</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br></pre></td><td class="code"><pre><span class="line">DiagnosticableTree (diagnostics.dart)</span><br><span class="line">    Widget (framework.dart) </span><br><span class="line">        PreferredSizeWidget (preferred_size.dart)</span><br><span class="line">            AppBar (app_bar.dart) </span><br><span class="line">            PreferredSize (preferred_size.dart)</span><br><span class="line">            TabBar (tabs.dart)</span><br><span class="line">        ProxyWidget (framework.dart)</span><br><span class="line">            InheritedWidget (framework.dart) </span><br><span class="line">                BottomNavigationBarTheme (bottom_navigation_bar_theme.dart)</span><br><span class="line">                ButtonBarTheme (button_bar_theme.dart)</span><br><span class="line">                CupertinoUserInterfaceLevel (interface_level.dart)</span><br><span class="line">                DataTableTheme (data_table_theme.dart)</span><br><span class="line">                DefaultAssetBundle (basic.dart)  </span><br><span class="line">                HeroControllerScope (navigator.dart)</span><br><span class="line">                InheritedModel (inherited_model.dart)</span><br><span class="line">                InheritedNotifier (inherited_notifier.dart) </span><br><span class="line">                InheritedTheme (inherited_theme.dart)  </span><br><span class="line">                MediaQuery (media_query.dart)</span><br><span class="line">                PrimaryScrollController (primary_scroll_controller.dart)</span><br><span class="line">                ScrollConfiguration (scroll_configuration.dart) </span><br><span class="line">            ParentDataWidget (framework.dart)  </span><br><span class="line">                Flexible (basic.dart)</span><br><span class="line">                KeepAlive (sliver.dart)</span><br><span class="line">                LayoutId (basic.dart)</span><br><span class="line">                Positioned (basic.dart)</span><br><span class="line">                TableCell (table.dart)</span><br><span class="line">        RenderObjectWidget (framework.dart) </span><br><span class="line">            ConstrainedLayoutBuilder (layout_builder.dart)</span><br><span class="line">            LeafRenderObjectWidget (framework.dart)</span><br><span class="line">            ListWheelViewport (list_wheel_scroll_view.dart)</span><br><span class="line">            MultiChildRenderObjectWidget (framework.dart)</span><br><span class="line">            RenderObjectToWidgetAdapter (binding.dart)</span><br><span class="line">            SingleChildRenderObjectWidget (framework.dart)</span><br><span class="line">            SliverWithKeepAliveWidget (sliver.dart)</span><br><span class="line">            Table (table.dart)</span><br><span class="line">        StatefulWidget (framework.dart) </span><br><span class="line">            ActionListener (actions.dart)</span><br><span class="line">            Actions (actions.dart)</span><br><span class="line">            AndroidView (platform_view.dart)</span><br><span class="line">            AnimatedCrossFade (animated_cross_fade.dart)</span><br><span class="line">            AnimatedList (animated_list.dart)</span><br><span class="line">            AnimatedSwitcher (animated_switcher.dart)</span><br><span class="line">            AnimatedWidget (transitions.dart)</span><br><span class="line">            AppBar (app_bar.dart) </span><br><span class="line">            ...</span><br><span class="line">        StatelessWidget (framework.dart) </span><br><span class="line">            AboutDialog (about.dart)</span><br><span class="line">            AboutListTile (about.dart)</span><br><span class="line">            ActionChip (chip.dart)</span><br><span class="line">            AlertDialog (dialog.dart) </span><br><span class="line">            ...</span><br></pre></td></tr></tbody></table></figure>

<h2 id="BuildContext"><a href="#BuildContext" class="headerlink" title="BuildContext"></a>BuildContext</h2><p>用于组织Element树和RenderObject树,它和Widget树的分层结构很相似,每个Widget都有一个与之应一个Element.</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line">BuildContext (framework.dart)</span><br><span class="line">    <span class="built_in">Element</span> (framework.dart)</span><br><span class="line">        ComponentElement (framework.dart)  </span><br><span class="line">            ProxyElement (framework.dart) &lt;=&gt; ProxyWidget</span><br><span class="line">                InheritedElement (framework.dart) &lt;=&gt; InheritedWidget</span><br><span class="line">                ParentDataElement (framework.dart) &lt;=&gt; ParentDataWidget</span><br><span class="line">            StatefulElement (framework.dart) &lt;=&gt; StatefulWidget</span><br><span class="line">            StatelessElement (framework.dart) &lt;=&gt; StatelessWidget </span><br><span class="line">        RenderObjectElement (framework.dart) &lt;=&gt; RenderObjectWidget</span><br><span class="line">            LeafRenderObjectElement (framework.dart)</span><br><span class="line">            ListWheelElement (list_wheel_scroll_view.dart)</span><br><span class="line">            MultiChildRenderObjectElement (framework.dart) </span><br><span class="line">            RootRenderObjectElement (framework.dart) </span><br><span class="line">            SingleChildRenderObjectElement (framework.dart) </span><br><span class="line">            SliverMultiBoxAdaptorElement (sliver.dart) </span><br></pre></td></tr></tbody></table></figure>

<h2 id="RenderObject"><a href="#RenderObject" class="headerlink" title="RenderObject"></a>RenderObject</h2><p>渲染树元素的基类,它负责提供界面渲染所需要的信息,同时也负责点击的处理,layout/paint也是这个renderObject中执行</p>
<p>它实现了<code>HitTestTarget</code>,并在启动时通过<code>RendererBinding</code>来监听手势触摸事件,所以它是可以拦截处理<code>hitTest</code>事件的</p>
<p>每个RenderObject对象都有一个ParentData属性,用于描述父widget的相关的render信息,以便作用于子Widget,如对齐,尺寸</p>
<p>主要实现类如下:</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">HitTestTarget (hit_test.dart)</span><br><span class="line">    GestureBinding (binding.dart)</span><br><span class="line">        RendererBinding (binding.dart)</span><br><span class="line">        ...</span><br><span class="line">    RenderObject (object.dart) </span><br><span class="line">        RenderAbstractViewport (viewport.dart) </span><br><span class="line">        RenderBox (box.dart) </span><br><span class="line">        RenderObjectWithChildMixin (object.dart) </span><br><span class="line">        RenderSliver (sliver.dart) </span><br><span class="line">        RenderView (view.dart) </span><br></pre></td></tr></tbody></table></figure>

<p>其中比较常用的有<code>RenderObject</code>和<code>RenderSliver</code><br>RenderObject是一个盒子渲染对象，有自己的坐标系,从左上角开始为(0,0),layout/paint</p>
<p>RenderObject是二维笛卡尔坐标系统中的渲染对象</p>
<h2 id="PaintingContext"><a href="#PaintingContext" class="headerlink" title="PaintingContext"></a>PaintingContext</h2><figure class="highlight plain"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">graph TB;</span><br><span class="line"></span><br><span class="line">A[ClipContext]</span><br></pre></td></tr></tbody></table></figure>

<h2 id="Flutter-Layer"><a href="#Flutter-Layer" class="headerlink" title="Flutter Layer"></a>Flutter Layer</h2><p>layer是flutter framework输出的最终产物,之后进入flutter engine进行图形的光栅</p>
<p>AbstractNode (node.dart)<br>    Layer (layer.dart)<br>        _InspectorOverlayLayer (widget_inspector.dart)<br>        _ProxyLayer (widget_inspector.dart)<br>        ContainerLayer (layer.dart)<br>            AnnotatedRegionLayer (layer.dart)<br>            BackdropFilterLayer (layer.dart)<br>            ClipPathLayer (layer.dart)<br>            ClipRectLayer (layer.dart)<br>            ClipRRectLayer (layer.dart)<br>            ColorFilterLayer (layer.dart)<br>            FollowerLayer (layer.dart)<br>            ImageFilterLayer (layer.dart)<br>            LeaderLayer (layer.dart)<br>            OffsetLayer (layer.dart)<br>                _ScreenshotContainerLayer (widget_inspector.dart)<br>                TransformLayer (layer.dart)<br>            OpacityLayer (layer.dart)<br>            PhysicalModelLayer (layer.dart)<br>            ShaderMaskLayer (layer.dart)<br>        PerformanceOverlayLayer (layer.dart)<br>        PictureLayer (layer.dart)<br>        PlatformViewLayer (layer.dart)<br>        TextureLayer (layer.dart)</p>
<h2 id="test"><a href="#test" class="headerlink" title="test"></a>test</h2><p>AbstractNode</p>
<figure class="highlight plain"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line">_depth</span><br><span class="line">_owner</span><br><span class="line">_parent</span><br><span class="line">attached</span><br><span class="line">depth</span><br><span class="line">owner</span><br><span class="line">parent</span><br><span class="line">redepthChildren</span><br></pre></td></tr></tbody></table></figure>

<p>RenderObject 方法</p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br></pre></td><td class="code"><pre><span class="line">_cleanChildRelayoutBoundary</span><br><span class="line">_cleanRelayoutBoundary</span><br><span class="line">_constraints</span><br><span class="line">_doingThisLayoutWithCallback</span><br><span class="line">_layer</span><br><span class="line">_layoutWithoutResize</span><br><span class="line">_needsCompositing</span><br><span class="line">_needsCompositingBitsUpdate</span><br><span class="line">_needsLayout</span><br><span class="line">_needsPaint</span><br><span class="line">_needsSemanticsUpdate</span><br><span class="line">_paintWithContext</span><br><span class="line">_relayoutBoundary</span><br><span class="line">_skippedPaintingOnLayer</span><br><span class="line">_updateCompositingBits</span><br><span class="line">applyPaintTransform</span><br><span class="line">getTransformTo</span><br><span class="line">isRepaintBoundary</span><br><span class="line">layout</span><br><span class="line">markNeedsCompositingBitsUpdate</span><br><span class="line">markNeedsLayout</span><br><span class="line">markNeedsLayoutForSizedByParentChange</span><br><span class="line">markNeedsPaint</span><br><span class="line">markNeedsSemanticsUpdate</span><br><span class="line">needsCompositing</span><br><span class="line">paint</span><br><span class="line">paintBounds</span><br><span class="line">parentData</span><br><span class="line">reassemble</span><br><span class="line">replaceRootLayer</span><br><span class="line">rotate</span><br><span class="line">scheduleInitialLayout</span><br><span class="line">scheduleInitialPaint</span><br><span class="line">scheduleInitialSemantics</span><br><span class="line">semanticBounds</span><br><span class="line">sendSemanticsEvent</span><br><span class="line">setupParentData</span><br><span class="line">showOnScreen</span><br><span class="line">visitChildren</span><br><span class="line">visitChildrenForSemantics</span><br></pre></td></tr></tbody></table></figure>


<h2 id="Flutter渲染流程"><a href="#Flutter渲染流程" class="headerlink" title="Flutter渲染流程"></a>Flutter渲染流程</h2><figure class="highlight plain"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br></pre></td><td class="code"><pre><span class="line"></span><br><span class="line">graph LR;</span><br><span class="line">  subgraph Rending Pipleline-UI Thread;</span><br><span class="line">      A1(Animate)--&gt;A2</span><br><span class="line">      A2(Build)--&gt;A3</span><br><span class="line">      A3(Layout)--&gt;A4</span><br><span class="line">      A4(Paint)--&gt;A5</span><br><span class="line">      A5(Sumbit)</span><br><span class="line">  end</span><br><span class="line">  </span><br><span class="line">  subgraph Graphics Pipline-GPU thread;</span><br><span class="line">      C1(Raster &amp; Compositor) </span><br><span class="line">  end</span><br><span class="line">  </span><br><span class="line">  subgraph GPU</span><br><span class="line">      B1(GPU)</span><br><span class="line">  end</span><br><span class="line">  B1--Vsyc--&gt;A1</span><br><span class="line">  A5--layers--&gt;C1</span><br><span class="line">  C1--&gt;B1</span><br><span class="line">  </span><br></pre></td></tr></tbody></table></figure>


<p>Animator -&gt; build -&gt; layout -&gt; painting -&gt; compsiting </p>
<figure class="highlight dart"><table><tbody><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line"></span><br><span class="line"><span class="keyword">void</span> main() {</span><br><span class="line">  <span class="comment">///<span class="markdown">1.记录 graphical operations</span></span></span><br><span class="line">  PictureRecorder recorder = PictureRecorder();</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown">2.画布, engine(C++)到 dart层的桥接,暴露了很多绘制api</span></span></span><br><span class="line">  Canvas canvas = Canvas(recorder);</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown">3.生成绘制画笔</span></span></span><br><span class="line">  Paint paint = Paint()</span><br><span class="line">    ..color = Colors.red</span><br><span class="line">    ..strokeWidth = <span class="number">5.0</span>;</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown">4.绘制圆环指令</span></span></span><br><span class="line">  canvas.drawCircle(Offset(<span class="number">200.0</span>, <span class="number">200.0</span>), <span class="number">200.0</span>, paint);</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown">5.结束绘制指令记录,记录的是native的绘制指令</span></span></span><br><span class="line">  Picture picture = recorder.endRecording();</span><br><span class="line">  SceneBuilder sceneBuilder = SceneBuilder();</span><br><span class="line">  sceneBuilder.pushOffset(<span class="number">0.0</span>, <span class="number">0.0</span>);</span><br><span class="line">  sceneBuilder.addPicture(Offset.zero, picture);</span><br><span class="line"></span><br><span class="line">  sceneBuilder.pop();</span><br><span class="line">  Scene scene = sceneBuilder.build();</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown"><span class="bullet">6.</span> 设置onDraw的回调钩子</span></span></span><br><span class="line">  <span class="built_in">window</span>.onDrawFrame = () {</span><br><span class="line">    <span class="built_in">window</span>.render(scene);</span><br><span class="line">  };</span><br><span class="line"></span><br><span class="line">  <span class="comment">///<span class="markdown"><span class="bullet">7.</span> 通知engine有新的scene待渲染</span></span></span><br><span class="line">  <span class="built_in">window</span>.scheduleFrame();</span><br><span class="line">}</span><br></pre></td></tr></tbody></table></figure>


                
            </div>
            <hr/>

            

    <div class="reprint" id="reprint-statement">
        
            <div class="reprint__author">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-user">
                        jiodg45:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="/jiodg45/about" rel="external nofollow noreferrer">Longxiang.Guo</a>
                </span>
            </div>
            <div class="reprint__type">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-link">
                        文章链接:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="https://jiodg45.gitee.io/jiodg45/jiodg45/2021/04/10/flutter/flutter-shape/">https://jiodg45.gitee.io/jiodg45/jiodg45/2021/04/10/flutter/flutter-shape/</a>
                </span>
            </div>
            <div class="reprint__notice">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-copyright">
                        版权声明:
                    </i>
                </span>
                <span class="reprint-info">
                    本博客所有文章除特別声明外，均采用
                    <a href="https://creativecommons.org/licenses/by/4.0/deed.zh" rel="external nofollow noreferrer" target="_blank">CC BY 4.0</a>
                    许可协议。转载请注明来源
                    <a href="/jiodg45/about" target="_blank">Longxiang.Guo</a>
                    !
                </span>
            </div>
        
    </div>

    <script async defer>
      document.addEventListener("copy", function (e) {
        let toastHTML = '<span>复制成功，请遵循本文的转载规则</span><button class="btn-flat toast-action" onclick="navToReprintStatement()" style="font-size: smaller">查看</a>';
        M.toast({html: toastHTML})
      });

      function navToReprintStatement() {
        $("html, body").animate({scrollTop: $("#reprint-statement").offset().top - 80}, 800);
      }
    </script>



            <div class="tag_share" style="display: block;">
                <div class="post-meta__tag-list" style="display: inline-block;">
                    
                        <div class="article-tag">
                            <span class="chip bg-color">无标签</span>
                        </div>
                    
                </div>
                <div class="post_share" style="zoom: 80%; width: fit-content; display: inline-block; float: right; margin: -0.15rem 0;">
                    <link rel="stylesheet" type="text/css" href="/jiodg45/libs/share/css/share.min.css">
<div id="article-share">

    
    <div class="social-share" data-sites="twitter,facebook,google,qq,qzone,wechat,weibo,douban,linkedin" data-wechat-qrcode-helper="<p>微信扫一扫即可分享！</p>"></div>
    <script src="/jiodg45/libs/share/js/social-share.min.js"></script>
    

    

</div>

                </div>
            </div>
            
        </div>
    </div>

    

    

    

    

    

    

    

    

    

<article id="prenext-posts" class="prev-next articles">
    <div class="row article-row">
        
        <div class="article col s12 m6" data-aos="fade-up" data-aos="fade-up">
            <div class="article-badge left-badge text-color">
                <i class="far fa-dot-circle"></i>&nbsp;本篇
            </div>
            <div class="card">
                <a href="/jiodg45/2021/04/10/flutter/flutter-shape/">
                    <div class="card-image">
                        
                        
                        <img src="/jiodg45/medias/featureimages/0.jpg" class="responsive-img" alt="">
                        
                        <span class="card-title"></span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            
                        
                    </div>
                    <div class="publish-info">
                            <span class="publish-date">
                                <i class="far fa-clock fa-fw icon-date"></i>2021-04-10
                            </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-user fa-fw"></i>
                            Longxiang.Guo
                            
                        </span>
                    </div>
                </div>

                
            </div>
        </div>
        
        
        <div class="article col s12 m6" data-aos="fade-up">
            <div class="article-badge right-badge text-color">
                下一篇&nbsp;<i class="fas fa-chevron-right"></i>
            </div>
            <div class="card">
                <a href="/jiodg45/2021/03/23/ios/net-working/">
                    <div class="card-image">
                        
                        
                        <img src="/jiodg45/medias/featureimages/0.jpg" class="responsive-img" alt="">
                        
                        <span class="card-title"></span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            
                        
                    </div>
                    <div class="publish-info">
                            <span class="publish-date">
                                <i class="far fa-clock fa-fw icon-date"></i>2021-03-23
                            </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-user fa-fw"></i>
                            Longxiang.Guo
                            
                        </span>
                    </div>
                </div>
                
            </div>
        </div>
        
    </div>
</article>

</div>



<!-- 代码块功能依赖 -->
<script type="text/javascript" src="/jiodg45/libs/codeBlock/codeBlockFuction.js"></script>

<!-- 代码语言 -->

<script type="text/javascript" src="/jiodg45/libs/codeBlock/codeLang.js"></script>


<!-- 代码块复制 -->

<script type="text/javascript" src="/jiodg45/libs/codeBlock/codeCopy.js"></script>


<!-- 代码块收缩 -->

<script type="text/javascript" src="/jiodg45/libs/codeBlock/codeShrink.js"></script>


    </div>
    <div id="toc-aside" class="expanded col l3 hide-on-med-and-down">
        <div class="toc-widget card" style="background-color: white;">
            <div class="toc-title"><i class="far fa-list-alt"></i>&nbsp;&nbsp;目录</div>
            <div id="toc-content"></div>
        </div>
    </div>
</div>

<!-- TOC 悬浮按钮. -->

<div id="floating-toc-btn" class="hide-on-med-and-down">
    <a class="btn-floating btn-large bg-color">
        <i class="fas fa-list-ul"></i>
    </a>
</div>


<script src="/jiodg45/libs/tocbot/tocbot.min.js"></script>
<script>
    $(function () {
        tocbot.init({
            tocSelector: '#toc-content',
            contentSelector: '#articleContent',
            headingsOffset: -($(window).height() * 0.4 - 45),
            collapseDepth: Number('0'),
            headingSelector: 'h2, h3, h4'
        });

        // modify the toc link href to support Chinese.
        let i = 0;
        let tocHeading = 'toc-heading-';
        $('#toc-content a').each(function () {
            $(this).attr('href', '#' + tocHeading + (++i));
        });

        // modify the heading title id to support Chinese.
        i = 0;
        $('#articleContent').children('h2, h3, h4').each(function () {
            $(this).attr('id', tocHeading + (++i));
        });

        // Set scroll toc fixed.
        let tocHeight = parseInt($(window).height() * 0.4 - 64);
        let $tocWidget = $('.toc-widget');
        $(window).scroll(function () {
            let scroll = $(window).scrollTop();
            /* add post toc fixed. */
            if (scroll > tocHeight) {
                $tocWidget.addClass('toc-fixed');
            } else {
                $tocWidget.removeClass('toc-fixed');
            }
        });

        
        /* 修复文章卡片 div 的宽度. */
        let fixPostCardWidth = function (srcId, targetId) {
            let srcDiv = $('#' + srcId);
            if (srcDiv.length === 0) {
                return;
            }

            let w = srcDiv.width();
            if (w >= 450) {
                w = w + 21;
            } else if (w >= 350 && w < 450) {
                w = w + 18;
            } else if (w >= 300 && w < 350) {
                w = w + 16;
            } else {
                w = w + 14;
            }
            $('#' + targetId).width(w);
        };

        // 切换TOC目录展开收缩的相关操作.
        const expandedClass = 'expanded';
        let $tocAside = $('#toc-aside');
        let $mainContent = $('#main-content');
        $('#floating-toc-btn .btn-floating').click(function () {
            if ($tocAside.hasClass(expandedClass)) {
                $tocAside.removeClass(expandedClass).hide();
                $mainContent.removeClass('l9');
            } else {
                $tocAside.addClass(expandedClass).show();
                $mainContent.addClass('l9');
            }
            fixPostCardWidth('artDetail', 'prenext-posts');
        });
        
    });
</script>

    

</main>




    <footer class="page-footer bg-color">
    
        <link rel="stylesheet" href="/jiodg45/libs/aplayer/APlayer.min.css">
<style>
    .aplayer .aplayer-lrc p {
        
        display: none;
        
        font-size: 12px;
        font-weight: 700;
        line-height: 16px !important;
    }

    .aplayer .aplayer-lrc p.aplayer-lrc-current {
        
        display: none;
        
        font-size: 15px;
        color: #42b983;
    }

    
    .aplayer.aplayer-fixed.aplayer-narrow .aplayer-body {
        left: -66px !important;
    }

    .aplayer.aplayer-fixed.aplayer-narrow .aplayer-body:hover {
        left: 0px !important;
    }

    
</style>
<div class="">
    
    <div class="row">
        <meting-js class="col l8 offset-l2 m10 offset-m1 s12"
                   server="netease"
                   type="playlist"
                   id="503838841"
                   fixed='true'
                   autoplay='false'
                   theme='#42b983'
                   loop='all'
                   order='random'
                   preload='auto'
                   volume='0.7'
                   list-folded='true'
        >
        </meting-js>
    </div>
</div>

<script src="/jiodg45/libs/aplayer/APlayer.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/meting@2/dist/Meting.min.js"></script>

    
    <div class="container row center-align" style="margin-bottom: 0px !important;">
        <div class="col s12 m8 l8 copy-right">
            Copyright&nbsp;&copy;
            
                <span id="year">2019-2021</span>
            
            <span id="year">2019</span>
            <a href="/jiodg45/about" target="_blank">Longxiang.Guo</a>
            |&nbsp;Powered by&nbsp;<a href="https://hexo.io/" target="_blank">Hexo</a>
            |&nbsp;Theme&nbsp;<a href="https://github.com/blinkfox/hexo-theme-matery" target="_blank">Matery</a>
            <br>
            
            
            
            
            
            
            <span id="busuanzi_container_site_pv">
                |&nbsp;<i class="far fa-eye"></i>&nbsp;总访问量:&nbsp;<span id="busuanzi_value_site_pv"
                    class="white-color"></span>&nbsp;次
            </span>
            
            
            <span id="busuanzi_container_site_uv">
                |&nbsp;<i class="fas fa-users"></i>&nbsp;总访问人数:&nbsp;<span id="busuanzi_value_site_uv"
                    class="white-color"></span>&nbsp;人
            </span>
            
            <br>
            
            <br>
            
        </div>
        <div class="col s12 m4 l4 social-link social-statis">
    <a href="https://github.com/LongXiangGuo" class="tooltipped" target="_blank" data-tooltip="访问我的GitHub" data-position="top" data-delay="50">
        <i class="fab fa-github"></i>
    </a>



    <a href="mailto:290657563@qq.com" class="tooltipped" target="_blank" data-tooltip="邮件联系我" data-position="top" data-delay="50">
        <i class="fas fa-envelope-open"></i>
    </a>







    <a href="tencent://AddContact/?fromId=50&fromSubId=1&subcmd=all&uin=290657563" class="tooltipped" target="_blank" data-tooltip="QQ联系我: 290657563" data-position="top" data-delay="50">
        <i class="fab fa-qq"></i>
    </a>







</div>
    </div>
</footer>

<div class="progress-bar"></div>


    <!-- 搜索遮罩框 -->
<div id="searchModal" class="modal">
    <div class="modal-content">
        <div class="search-header">
            <span class="title"><i class="fas fa-search"></i>&nbsp;&nbsp;搜索</span>
            <input type="search" id="searchInput" name="s" placeholder="请输入搜索的关键字"
                   class="search-input">
        </div>
        <div id="searchResult"></div>
    </div>
</div>

<script type="text/javascript">
$(function () {
    var searchFunc = function (path, search_id, content_id) {
        'use strict';
        $.ajax({
            url: path,
            dataType: "xml",
            success: function (xmlResponse) {
                // get the contents from search data
                var datas = $("entry", xmlResponse).map(function () {
                    return {
                        title: $("title", this).text(),
                        content: $("content", this).text(),
                        url: $("url", this).text()
                    };
                }).get();
                var $input = document.getElementById(search_id);
                var $resultContent = document.getElementById(content_id);
                $input.addEventListener('input', function () {
                    var str = '<ul class=\"search-result-list\">';
                    var keywords = this.value.trim().toLowerCase().split(/[\s\-]+/);
                    $resultContent.innerHTML = "";
                    if (this.value.trim().length <= 0) {
                        return;
                    }
                    // perform local searching
                    datas.forEach(function (data) {
                        var isMatch = true;
                        var data_title = data.title.trim().toLowerCase();
                        var data_content = data.content.trim().replace(/<[^>]+>/g, "").toLowerCase();
                        var data_url = data.url;
                        data_url = data_url.indexOf('/') === 0 ? data.url : '/' + data_url;
                        var index_title = -1;
                        var index_content = -1;
                        var first_occur = -1;
                        // only match artiles with not empty titles and contents
                        if (data_title !== '' && data_content !== '') {
                            keywords.forEach(function (keyword, i) {
                                index_title = data_title.indexOf(keyword);
                                index_content = data_content.indexOf(keyword);
                                if (index_title < 0 && index_content < 0) {
                                    isMatch = false;
                                } else {
                                    if (index_content < 0) {
                                        index_content = 0;
                                    }
                                    if (i === 0) {
                                        first_occur = index_content;
                                    }
                                }
                            });
                        }
                        // show search results
                        if (isMatch) {
                            str += "<li><a href='" + data_url + "' class='search-result-title'>" + data_title + "</a>";
                            var content = data.content.trim().replace(/<[^>]+>/g, "");
                            if (first_occur >= 0) {
                                // cut out 100 characters
                                var start = first_occur - 20;
                                var end = first_occur + 80;
                                if (start < 0) {
                                    start = 0;
                                }
                                if (start === 0) {
                                    end = 100;
                                }
                                if (end > content.length) {
                                    end = content.length;
                                }
                                var match_content = content.substr(start, end);
                                // highlight all keywords
                                keywords.forEach(function (keyword) {
                                    var regS = new RegExp(keyword, "gi");
                                    match_content = match_content.replace(regS, "<em class=\"search-keyword\">" + keyword + "</em>");
                                });

                                str += "<p class=\"search-result\">" + match_content + "...</p>"
                            }
                            str += "</li>";
                        }
                    });
                    str += "</ul>";
                    $resultContent.innerHTML = str;
                });
            }
        });
    };

    searchFunc('/jiodg45/search.xml', 'searchInput', 'searchResult');
});
</script>

    <!-- 回到顶部按钮 -->
<div id="backTop" class="top-scroll">
    <a class="btn-floating btn-large waves-effect waves-light" href="#!">
        <i class="fas fa-arrow-up"></i>
    </a>
</div>


    <script src="/jiodg45/libs/materialize/materialize.min.js"></script>
    <script src="/jiodg45/libs/masonry/masonry.pkgd.min.js"></script>
    <script src="/jiodg45/libs/aos/aos.js"></script>
    <script src="/jiodg45/libs/scrollprogress/scrollProgress.min.js"></script>
    <script src="/jiodg45/libs/lightGallery/js/lightgallery-all.min.js"></script>
    <script src="/jiodg45/js/matery.js"></script>

    <!-- Baidu Analytics -->

    <!-- Baidu Push -->

<script>
    (function () {
        var bp = document.createElement('script');
        var curProtocol = window.location.protocol.split(':')[0];
        if (curProtocol === 'https') {
            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
        } else {
            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
        }
        var s = document.getElementsByTagName("script")[0];
        s.parentNode.insertBefore(bp, s);
    })();
</script>

    
    <script src="/jiodg45/libs/others/clicklove.js" async="async"></script>
    
    
    <script async src="/jiodg45/libs/others/busuanzi.pure.mini.js"></script>
    

    

    

    <!--腾讯兔小巢-->
    
    

    

    

    
    <script src="/jiodg45/libs/instantpage/instantpage.js" type="module"></script>
    

</body>

</html>
